全球液化石油气运输网络贸易社区特征及其演化分析

液化石油气在全球清洁能源消耗市场中扮演着极为重要的角色,其通过船舶在不同港口之间进行运输,而港口之间通过局部密集的运输关系,形成了联系极为紧密的贸易社区。采用复杂网络社区探测方法,基于2013—2017年全球液化石油气船舶轨迹大数据构建运输网络,并对其贸易社区特征及其演化趋势开展分析。结果表明：（1）液化石油气（Liquefied Petroleum Gas,LPG）贸易社区内的港口之间的联系更加紧密,不同社区内的枢纽港口联系也日益紧密;（2）各个贸易社区的规模呈现出增长趋势,且同一社区内的港口在地理空间上变得更为集聚;（3）亚太地区、中东、西北欧和地中海地区形成的社区在全球LPG贸易中一直保持着重要地位,而随着时间推移,美洲社区已逐渐从一个相对孤立的社区发展成为与其他社区存在紧密联系的社区。     

船上生活饮用水中亚硝酸盐污染及其治理

经测定，某航次船上饮用开水中亚硝酸盐的浓度为0.180mg/dm^3，超过GB8537-87标准35倍；冷自来水中为1.76mg/dm^3，超标350倍。航次结束后，从码头自来水管取的四份水样中亚硝酸氮则全部未检出。本文报道了船上饮用水与生活用水受到具有致癌性的亚硝酸盐污梁，并为消除亚硝酸盐污染提出了对策。     

The safety of fetoscopy: (I). Effect of umbilical vessel puncture on the fetal heart rate and cord histology

The fetal heart rate (FHR) was continuously monitored during 42 umbilical vessel punctures performed at the placental insertion of the cord in 24 diagnostic fetoscopies in which pure fetal blood was obtained. In only one patient did a deceleration first appear during puncture and aspiration of fetal blood. In two patients decelerations preceded fetoscopy and in two others they began during the fetoscopy but before puncture of an umbilical vessel. In 19 patients, the FHR did not change at all during the procedure. Fetal haemorrhage after sampling was either absent or minimal. Six pregnancies were terminated because a positive diagnosis had been made and 18 healthy babies were born. Umbilical cords were examined after 7 terminations of pregnancy and after 6 deliveries. In the former group the puncture could just be seen with the naked eye and the needle track was demonstrated histologically in 6. No traces of the puncture or other abnormalities were found in the cords after delivery. Fetal blood sampling from umbilical cord vessels, particularly at the placental insertion of the cord, is the technique of choice since pure fetal blood can be obtained without increasing the risk of fetoscopy.     

On the thermal rupture of 1.9 m propane pressure vessels with defects in their thermal protection system

This paper describes the results from a series of fire tests that were carried out to measure the effect of defects in thermal protection systems on fire engulfed propane pressure vessels.

In North America thermal protection is used to protect dangerous goods rail tank-cars from accidental fire impingement. They are designed so that a tank-car will not rupture for 100 min in a defined engulfing fire, or 30 min in a defined torching fire. One common system includes a 13 mm blanket of high-temperature ceramic fibre thermal insulation covered with a 3 mm steel jacket. Recent inspections have shown that some tanks have significant defects in these thermal protection systems. This work was done to establish what levels of defect are acceptable from a safety standpoint.

The tests were conducted using 1890 l (500 US gallon) ASME code propane pressure vessels (commonly called tanks in the propane industry). The defects tested covered 8% and 15% of the tank surface. The tanks were 25% engulfed in a fire that simulated a hydrocarbon pool fire with an effective blackbody temperature of 870 °C.

The fire testing showed that even relatively small defects can result in tank rupture if the defect area is engulfed in a severe fire, and the defect area is not wetted by liquid from the inside. A wall failure prediction technique based on uniaxial high-temperature stress rupture test data has been developed and agrees well with the observed failure times.     

南京理工大学高压实验室及其研制高压水射流切割机

南京理工大学高压实验室自８０年代初建立以来，在高压容器及武器发射管的自紧理论和工程应用、高压零部件研制、高压传感器和信号放大显示系统、高压介质等方面做了大量的工作。９３年以来，进行了水射流切割机的研制工作，解决了超高压缸体的动态密封、高压缸体的自增强、无触点式换向传感器、内衬不锈钢组合型高压容器等诸多问题，试制成功了水射流切割机样机。     

带防腐层在役压力容器表面磁粉探伤灵敏度的试验研究

采用人工裂纹试样的方法 ,模拟压力容器涂刷油漆防腐层的状况进行磁粉探伤 ,得出了油漆防腐层厚度与裂纹检出灵敏度的定量关系 ;结合CVDA《压力容器缺陷评定》规范 ,探讨了试验方法对一般在役压力容器带有油漆的情况下 ,进行磁粉探伤检验的可行性。研究表明 :采用交流磁化法进行探伤 ,当漆层厚度大约小于2 5 0 μm时 ,灵敏度影响较小 ,同时亦表明不宜使用直流磁化方法。该结论对承受低应力工况条件下的压力容器安全质量检验和评估 ,具有重要参考价值     

灰色层次结构模型在故障树分析中的应用

故障树分析技术对于复杂系统的故障诊断具有重要应用价值,提出把故障树看作2层灰色结构,通过建立灰色层次结构模型,给出判断各种故障模式发生可能性大小的一种通用方法.将其应用于压力容器爆炸事故的故障树分析,并取得了与实际情况吻合的满意结果.该方法为了解事故影响因素重要程度、控制事故发生和改进系统可靠性提供依据.     

Modeling of n-butane ignition, combustion, and preflame oxidation in the 20-l vessel

The objective of the study reported herein is to simulate various physical and chemical phenomena accompanying fuel-rich n-butane–oxygen mixture preparation, ignition, preflame oxidation, and combustion in the standard 20-l explosion vessel, by applying mathematical models. Based on the computational fluid dynamics (CFD) simulations of the mixing process and natural convection of the ignition kernel, as well as on the analysis of the detailed reaction mechanism of n-butane oxidation, laminar flame propagation, and self-ignition, possible explanations for the phenomena observed experimentally have been suggested. The results of the study indicate that seemingly inflammable mixtures can become hazardous depending on the mixture preparation procedure and forced ignition timing.     

密封充氢环境条件下固态电化学氢气传感器效应试验研究

目的研究密闭充氢环境下固态电化学氢气传感器效应。方法设计能模拟低氧、低氢和压力变化的密闭充氢环境,并在此环境中进行一系列氢气传感器效应试验,分析、评定试验数据。结果得到了不同环境下氢气、氧气浓度随时间变化的规律,提出固态电化学氢气传感器的有效工作环境,并预测了其在不同贮存环境下的工作寿命。结论密闭充氢环境内压力和温度的变化对固态电化学氢气传感器影响较大,湿度影响较小,注气检定合格的氢气传感器,在密封容器内扩散式检定,不合格率高,检定数据误差大于±5%FS。     

基于无人机高光谱遥感在太湖蓝藻水华监测中的一次应用

采用机载高光谱视频相机,在4个季节对太湖蓝藻进行7次、18个架次的有效拍摄。对拍摄到的高光谱影像进行辐射定标、几何拼接等预处理后,提取不同浓度蓝藻和水草等其他物体的高光谱数据,发现不同浓度的蓝藻光谱在680 nm后表现出较大差异。采用主成分分析（PCA）对高光谱数据降维后,结合k-近邻（kNN）分类算法,可实现对蓝藻的精准定位。定性识别结果经光谱预处理后,采用连续投影算法（SPA）进行特征波段提取,发现蓝藻光谱的季节差异主要表现在450 nm~570 nm和760 nm~910 nm波段。